RESUMO
Automotive brake-wear emissions are increasingly important in on-road particulate matter (PM) emission inventory. Previous studies reported a high level of PM emissions from the friction materials of light/medium-duty vehicles, but there are few data available from heavy-duty (HD) vehicles equipped with drum brakes despite their popularity (â¼85% in HD vehicle fleet). This study developed a novel tracer-gas-integrated method for brake-wear PM emission measurements and evaluated four HD vehicles on a chassis dynamometer that complied with regulatory exhaust emission testing requirements. Three class-6 vehicles with a similar test weight demonstrated repeatability, with the coefficient of variation in the range of 9-36%. Braking events increased PM concentrations by 3 orders of magnitude above the background level. Resuspension of brake-wear PM also occurred during acceleration and contributed to 8-31% of the total PM2.5 mass. The class-6 vehicles had PM2.5 emissions from a single brake (0.7-1.5 mg/km/brake), generally similar to the level of tail-pipe exhaust PM emissions (0.7-1.5 mg/km/vehicle) of each vehicle. A class-8 vehicle exhibited brake-wear PM2.5 emissions (2.4-3.4 mg/km/brake) significantly higher than the tail-pipe exhaust PM emissions (â¼1.3 mg/km/vehicle). This article reports an exceptionally high level of brake-wear PM emissions measured directly from the drum brakes of HD vehicles.
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Poluentes Atmosféricos , Material Particulado , Material Particulado/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Emissões de Veículos/análise , Veículos AutomotoresRESUMO
The rodent ventral and primate anterior hippocampus have been implicated in approach-avoidance (AA) conflict processing. It is unclear, however, whether this structure contributes to AA conflict detection and/or resolution, and if its involvement extends to conditions of AA conflict devoid of spatial/contextual information. To investigate this, neurologically healthy human participants first learned to approach or avoid single novel visual objects with the goal of maximizing earned points. Approaching led to point gain and loss for positive and negative objects, respectively, whereas avoidance had no impact on score. Pairs of these objects, each possessing nonconflicting (positive-positive/negative-negative) or conflicting (positive-negative) valences, were then presented during functional magnetic resonance imaging. Participants either made an AA decision to score points (Decision task), indicated whether the objects had identical or differing valences (Memory task), or followed a visual instruction to approach or avoid (Action task). Converging multivariate and univariate results revealed that within the medial temporal lobe, perirhinal cortex, rather than the anterior hippocampus, was predominantly associated with object-based AA conflict resolution. We suggest the anterior hippocampus may not contribute equally to all learned AA conflict scenarios and that stimulus information type may be a critical and overlooked determinant of the neural mechanisms underlying AA conflict behavior.
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Aprendizagem da Esquiva , Comportamento de Escolha , Conflito Psicológico , Hipocampo/diagnóstico por imagem , Memória/fisiologia , Motivação , Córtex Perirrinal/diagnóstico por imagem , Lobo Temporal/diagnóstico por imagem , Adolescente , Adulto , Tomada de Decisões , Feminino , Neuroimagem Funcional , Hipocampo/fisiologia , Humanos , Aprendizagem/fisiologia , Imageamento por Ressonância Magnética , Masculino , Córtex Perirrinal/fisiologia , Lobo Temporal/fisiologia , Adulto JovemRESUMO
There has been much interest in how the hippocampus codes time in support of episodic memory. Notably, while rodent hippocampal neurons, including populations in subfield CA1, have been shown to represent the passage of time in the order of seconds between events, there is limited support for a similar mechanism in humans. Specifically, there is no clear evidence that human hippocampal activity during long-term memory processing is sensitive to temporal duration information that spans seconds. To address this gap, we asked participants to first learn short event sequences that varied in image content and interval durations. During fMRI, participants then completed a recognition memory task, as well as a recall phase in which they were required to mentally replay each sequence in as much detail as possible. We found that individual sequences could be classified using activity patterns in the anterior hippocampus during recognition memory. Critically, successful classification was dependent on the conjunction of event content and temporal structure information (with unsuccessful classification of image content or interval duration alone), and further analyses suggested that the most informative voxels resided in the anterior CA1. Additionally, a classifier trained on anterior CA1 recognition data could successfully identify individual sequences from the mental replay data, suggesting that similar activity patterns supported participants' recognition and recall memory. Our findings complement recent rodent hippocampal research, and provide evidence that long-term sequence memory representations in the human hippocampus can reflect duration information in the order of seconds.
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Hipocampo/fisiologia , Memória Episódica , Memória de Longo Prazo/fisiologia , Rememoração Mental/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Região CA1 Hipocampal/fisiologia , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Lobo Temporal/diagnóstico por imagem , Percepção do Tempo/fisiologiaRESUMO
Fundamental to the understanding of the functions of spatial cognition and attention is to clarify the underlying neural mechanisms. It is clear that relatively right-dominant activity in ventral and dorsal parieto-frontal cortex is associated with attentional reorienting, certain forms of mental imagery and spatial working memory for higher loads, while lesions mostly to right ventral areas cause spatial neglect with pathological attentional biases to the right side. In contrast, complementary leftward biases in healthy people, called pseudoneglect, have been associated with varying patterns of cortical activity. Notably, this inconsistency may be explained, at least in part, by the fact that pseudoneglect studies have often employed experimental paradigms that do not control sufficiently for cognitive processes unrelated to pseudoneglect. To address this issue, here we administered a carefully designed continuum of pseudoneglect and control tasks in healthy adults while using functional magnetic resonance imaging (fMRI). Data submitted to partial least square (PLS) imaging analysis yielded a significant latent variable that identified a right-dominant network of brain regions along the intra-occipital and -parietal sulci, frontal eye fields and right ventral cortex in association with perceptual pseudoneglect. Our results shed new light on the interplay of attentional and cognitive systems in pseudoneglect.
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Atenção/fisiologia , Encéfalo/fisiopatologia , Cognição/fisiologia , Transtornos da Percepção/fisiopatologia , Adulto , Feminino , Lateralidade Funcional/fisiologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória de Curto Prazo/fisiologia , Percepção Espacial/fisiologia , Percepção Visual/fisiologiaRESUMO
Sanitation is a major global challenge that is often addressed at national and international levels, while community opinions and beliefs are neglected. To promote water, sanitation and hygiene (WASH) we organized a cross-cultural knowledge exchange workshop to assess participatory methods for engaging local stakeholders. The workshop included 22 participants from all sectors of society. Practical solutions to sanitation challenges were identified and later shared with a local community. Qualitative and quantitative analyses were used to assess impact and showed participatory methods were highly valued to encourage information sharing among widely varied stakeholders, and that video was a particularly successful approach when engaging with local communities. An 8-month follow-up survey of village members revealed excellent information recall, positive behaviour changes and a desire for future visits. Our evidence suggests that community-based participation helped identify solutions to WASH issues affecting rural communities in resource-poor settings. Engaging in a multicultural knowledge-share was particularly valuable as it enabled participants to recognize they have common challenges and allowed them to share low-cost solutions from their different communities. Our use of video was widely viewed as an ideal means of circulating findings, as it communicated information to people with a wide variety of community roles and to all age groups. Its relevance was increased by adopting a culturally appropriate context by involving local communities in workshop activities. We recommend that research in low- and middle-income countries should be mindful of the environmental context in which WASH is implemented, and encourage acceptance by engaging with communities through the use of varied participatory methods.
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Higiene , Saneamento , Participação da Comunidade , Humanos , População Rural , UgandaRESUMO
Recent rodent work suggests the hippocampus may provide a temporal representation of event sequences, in which the order of events and the interval durations between them are encoded. There is, however, limited human evidence for the latter, in particular whether the hippocampus processes duration information pertaining to the passage of time rather than qualitative or quantitative changes in event content. We scanned participants while they made match-mismatch judgements on each trial between a study sequence of events and a subsequent test sequence. Participants explicitly remembered event order or interval duration information (Experiment 1), or monitored order only, with duration being manipulated implicitly (Experiment 2). Hippocampal study-test pattern similarity was significantly reduced by changes to order or duration in mismatch trials, even when duration was processed implicitly. Our findings suggest the human hippocampus processes short intervals within sequences and support the idea that duration information is integrated into hippocampal mnemonic representations.
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Neuroimagem Funcional/métodos , Hipocampo/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Memória Episódica , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção do Tempo/fisiologia , Adulto , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Adulto JovemRESUMO
BACKGROUND: Since 2012, The World Health Organization and UNICEF have advocated for community health workers (CHWs) to be trained in Integrated Community Case Management (iCCM) of common childhood illnesses, such as pneumonia. Despite the effectiveness of iCCM, CHWs face many barriers to accessing training. This pilot study compares traditional training with using locally made videos loaded onto low-cost Android tablets to train CHWs on the pneumonia component of iCCM. METHODS: We conducted a pilot randomised controlled trial with CHWs in the Mukono District of Uganda. The unit of randomisation was the sub-county level, and the unit of analysis was at the level of the individual CHW. Eligible CHWs had completed basic iCCM training but had not received any refresher training on the pneumonia component of iCCM in the preceding 2 years. CHWs in the control group received training in the recognition, treatment, and prevention of pneumonia as it is currently delivered, through a 1-day, in-person workshop. CHWs allocated to the intervention group received training via locally made educational videos hosted on low-cost Android tablets. The primary outcome was change in knowledge acquisition, assessed through a multiple choice questionnaire before and after training, and a post-training clinical assessment. The secondary outcome was a qualitative evaluation of CHW experiences of using the tablet platform. RESULTS: In the study, 129 CHWs were enrolled, 66 and 63 in the control and intervention groups respectively. CHWs in both groups demonstrated an improvement in multiple choice question test scores before and after training; however, there was no statistically significant difference in the improvement between groups (t = 1.15, p = 0.254). There was a statistically significant positive correlation (Pearson's r = 0.26, p = 0.03) linking years of education to improvement in test scores in the control group, which was not present in the intervention group. The majority of CHWs expressed satisfaction with the use of tablets as a training tool; however, some reported technical issues (n = 9). CONCLUSION: Tablet-based training is comparable to traditional training in terms of knowledge acquisition. It also proved to be feasible and a satisfactory means of delivering training to CHWs. Further research is required to understand the impacts of scaling such an intervention. TRIAL REGISTRATION: Registered on 23/11/2016 at clinicaltrials.gov ( NCT02971449 ).
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Antibacterianos/uso terapêutico , Agentes Comunitários de Saúde/educação , Instrução por Computador/métodos , Computadores de Mão , Educação Médica/métodos , Pneumonia/diagnóstico , Pneumonia/tratamento farmacológico , Gravação de Videoteipe , Adulto , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Pneumonia/prevenção & controle , UgandaRESUMO
Surprisingly little is known about how the brain combines spatial elements to form a coherent percept. Regions that may underlie this process include the hippocampus (HC) and parahippocampal place area (PPA), regions central to spatial perception but whose role in spatial coherency has not been explored. Participants were scanned with functional MRI while they judged whether Escher-like scenes were possible or impossible. Univariate analyses revealed differential HC and PPA involvement, with greater HC activity during spatial incoherency detection and more PPA activity during spatial coherency detection. Recognition and eye-tracking data ruled out long- or short-term memory confounds. Multivariate statistics demonstrated spatial coherency-dependent functional connectivity for the HC, but not PPA, with greater HC connectivity to various brain regions including lateral occipital complex during spatial incoherency detection. We suggest the PPA is preferentially involved during the perception of spatially coherent scenes, whereas the HC binds distinct features to create coherent representations. © 2016 Wiley Periodicals, Inc.
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Hipocampo/fisiologia , Giro Para-Hipocampal/fisiologia , Percepção Espacial/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Medições dos Movimentos Oculares , Movimentos Oculares/fisiologia , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Ilusões , Processamento de Imagem Assistida por Computador , Julgamento/fisiologia , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Giro Para-Hipocampal/diagnóstico por imagem , Estimulação Luminosa , Células de Lugar/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto JovemRESUMO
BACKGROUND: Uganda's national community health worker program involves volunteer Village Health Teams (VHTs) delivering basic health services and education. Evidence demonstrates their positive impact on health outcomes, particularly for Ugandans who would otherwise lack access to health services. Despite their impact, VHTs are not optimally supported and attrition is a growing problem. In this study, we examined the support needs and existing challenges of VHTs in two Ugandan districts and evaluated specific factors associated with long-term retention. We report on findings from a standardized survey of VHTs and exploratory interviews with key stakeholders and draw conclusions that inform efforts to strengthen and sustain community health care delivery in Uganda. METHODS: A mixed-methods approach was employed through a survey of 134 individual VHT members and semi-structured interviews with six key stakeholders. Descriptive and bivariate regression analysis of quantitative survey data was performed along with thematic analysis of qualitative data from surveys and interviews. In the regression analysis, the dependent variable is 10-year anticipated longevity among VHTs, which asked respondents if they anticipate continuing to volunteer as VHTs for at least 10 more years if their current situation remains unchanged. RESULTS: VHTs desire additional support primarily in the forms of money (e.g. transportation allowance) and material supplies (e.g. rubber boots). VHTs commonly report difficult working conditions and describe a lack of respect from their communities and other health workers. If their current situation remains unchanged, 57% of VHTs anticipate remaining in their posts for at least 10 years. Anticipated 10-year longevity was positively associated with stronger partnerships with local health center staff and greater ease in home visiting. CONCLUSIONS: Supporting and retaining Uganda's VHTs would be enhanced by building stronger partnerships between VHTs and other health workers and regularly providing supplies and transportation allowances. Pursuing such measures would likely improve equity in access to healthcare for all Ugandans.
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Serviços de Saúde Comunitária/organização & administração , Agentes Comunitários de Saúde/organização & administração , Lealdade ao Trabalho , Apoio Social , Voluntários/psicologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Programas e Projetos de Saúde , Inquéritos e Questionários , Uganda , Voluntários/estatística & dados numéricos , Adulto JovemRESUMO
Rodent models of anxiety have implicated the ventral hippocampus in approach-avoidance conflict processing. Few studies have, however, examined whether the human hippocampus plays a similar role. We developed a novel decision-making paradigm to examine neural activity when participants made approach/avoidance decisions under conditions of high or absent approach-avoidance conflict. Critically, our task required participants to learn the associated reward/punishment values of previously neutral stimuli and controlled for mnemonic and spatial processing demands, both important issues given approach-avoidance behavior in humans is less tied to predation and foraging compared to rodents. Participants played a points-based game where they first attempted to maximize their score by determining which of a series of previously neutral image pairs should be approached or avoided. During functional magnetic resonance imaging, participants were then presented with novel pairings of these images. These pairings consisted of images of congruent or opposing learned valences, the latter creating conditions of high approach-avoidance conflict. A data-driven partial least squares multivariate analysis revealed two reliable patterns of activity, each revealing differential activity in the anterior hippocampus, the homolog of the rodent ventral hippocampus. The first was associated with greater hippocampal involvement during trials with high as opposed to no approach-avoidance conflict, regardless of approach or avoidance behavior. The second pattern encompassed greater hippocampal activity in a more anterior aspect during approach compared to avoid responses, for conflict and no-conflict conditions. Multivoxel pattern classification analyses yielded converging findings, underlining a role of the anterior hippocampus in approach-avoidance conflict decision making. SIGNIFICANCE STATEMENT: Approach-avoidance conflict has been linked to anxiety and occurs when a stimulus or situation is associated with reward and punishment. Although rodent work has implicated the hippocampus in approach-avoidance conflict processing, there is limited data on whether this role applies to learned, as opposed to innate, incentive values, and whether the human hippocampus plays a similar role. Using functional neuroimaging with a novel decision-making task that controlled for perceptual and mnemonic processing, we found that the human hippocampus was significantly active when approach-avoidance conflict was present for stimuli with learned incentive values. These findings demonstrate a role for the human hippocampus in approach-avoidance decision making that cannot be explained easily by hippocampal-dependent long-term memory or spatial cognition.
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Aprendizagem da Esquiva/fisiologia , Conflito Psicológico , Tomada de Decisões/fisiologia , Hipocampo/fisiologia , Imageamento por Ressonância Magnética/métodos , Estimulação Luminosa/métodos , Adulto , Feminino , Humanos , Masculino , Análise Multivariada , Tempo de Reação/fisiologia , Adulto JovemRESUMO
Recent work has demonstrated that the perirhinal cortex (PRC) supports conjunctive object representations that aid object recognition memory following visual object interference. It is unclear, however, how these representations interact with other brain regions implicated in mnemonic retrieval and how congruent and incongruent interference influences the processing of targets and foils during object recognition. To address this, multivariate partial least squares was applied to fMRI data acquired during an interference match-to-sample task, in which participants made object or scene recognition judgments after object or scene interference. This revealed a pattern of activity sensitive to object recognition following congruent (i.e., object) interference that included PRC, prefrontal, and parietal regions. Moreover, functional connectivity analysis revealed a common pattern of PRC connectivity across interference and recognition conditions. Examination of eye movements during the same task in a separate study revealed that participants gazed more at targets than foils during correct object recognition decisions, regardless of interference congruency. By contrast, participants viewed foils more than targets for incorrect object memory judgments, but only after congruent interference. Our findings suggest that congruent interference makes object foils appear familiar and that a network of regions, including PRC, is recruited to overcome the effects of interference.
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Encéfalo/fisiologia , Julgamento/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Adaptação Psicológica/fisiologia , Adulto , Mapeamento Encefálico , Medições dos Movimentos Oculares , Movimentos Oculares , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Testes Neuropsicológicos , Estimulação Luminosa , Adulto JovemRESUMO
An unresolved question in our understanding of the medial temporal lobes is how functional differences between structures pertaining to stimulus category relate to the distinction between item-based and contextually based recognition-memory processes. Specifically, it remains unclear whether perirhinal cortex (PrC) supports item-based familiarity signals for all stimulus categories or whether parahippocampal cortex (PhC) may also play a role for stimulus categories that are known to engage this structure in other task contexts. Here, we used multivoxel pattern analyses of fMRI data to compare patterns of activity in humans that are associated with the perceived familiarity of faces, buildings, and chairs. During scanning, participants judged the familiarity of previously studied and novel items from all three categories. Instances in which recognition was based on recollection were removed from all analyses. In right PrC, we found patterns of activity that distinguished familiar from novel faces. By contrast, in right PhC, we observed such patterns for buildings. Familiarity signals for chairs were present in both structures but shared little overlap with the patterns observed for faces and buildings on a more fine-grained scale. In the hippocampus, we found no evidence for familiarity signals for any object category. Our findings show that both PrC and PhC contribute to the assessment of item familiarity. They suggest that PhC does not only represent episodic context but can also represent item information for some object categories in recognition-memory decisions. In turn, our findings also indicate that the involvement of PrC in representing item familiarity is not ubiquitous.
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Face , Hipocampo/fisiologia , Giro Para-Hipocampal/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Julgamento/fisiologia , Imageamento por Ressonância Magnética , Masculino , Memória/fisiologia , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Adulto JovemRESUMO
Studies examining the neural correlates of face perception and recognition in humans have revealed multiple brain regions that appear to play a specialized role in face processing. These include an anterior portion of perirhinal cortex (PrC) that appears to be homologous to the face-selective 'anterior face patch' recently reported in non-human primates. Electrical stimulation studies in the macaque indicate that the anterior face patch is strongly connected with other face-selective patches of cortex, even in the absence of face stimuli. The intrinsic functional connectivity of face-selective PrC and other regions of the face-processing network in humans are currently less well understood. Here, we examined resting-state fMRI connectivity across five face-selective regions in the right hemisphere that were identified with separate functional localizer scans: the PrC, amygdala (Amg), superior temporal sulcus, fusiform face area (FFA), and occipital face area. A partial correlation technique, controlling for fluctuations in occipitotemporal cortex that were not face specific, revealed connectivity between the PrC and the FFA, as well as the Amg. When examining the 'unique' connectivity of PrC within this face processing network, we found that the connectivity between the PrC and the FFA as well as that between the PrC and the Amg persisted even after controlling for potential mediating effects of other face-selective regions. Lastly, we examined the behavioral relevance of PrC connectivity by examining inter-individual differences in resting-state fluctuations in relation to differences in behavioral performance for a forced-choice recognition memory task that involved judgments on upright and inverted faces. This analysis revealed a significant correlation between the increased accuracy for upright faces (i.e., the face inversion effect) and the strength of connectivity between the PrC and the FFA. Together, these findings point to a high degree of functional integration of face-selective aspects of PrC in the face processing network with notable behavioral relevance.
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Córtex Cerebral/fisiologia , Conectoma/métodos , Face , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Adulto , Feminino , Humanos , Masculino , Vias Neurais/fisiologia , Descanso/fisiologia , Adulto JovemRESUMO
N-acylphosphatidylethanolamines (NAPEs) are naturally occurring derivatives of phosphatidylethanolmine (PE) in which the PE amino group is attached to an acyl chain. Given their occurrence in natural systems, there is interest in knowing the effect of NAPEs on membrane dynamic structure and function. This study examines the ability of NAPEs to affect the association of the cytochrome c and Zn-heme cytochrome c with the surface of bilayer membranes. Fluorescence titration experiments show that cationic cytochrome c has the same high affinity for the surfaces of anionic vesicles that are rich in NAPEs or diplalmitoyphosphatidylglycerol (DPPG) but the protein/membrane interaction in each case is quite different. Cytochrome c adsorption to DPPG membranes is relatively irreversible due to the DPPG molecules adopting an extended conformation that promotes strong hydrophobic contact with the adsorbed protein. In contrast, cytochrome c association with N-acyl DPPE membranes is due primarily to reversible electrostatic interactions with the anionic headgroup, and not hydrophobic contact with the N-acyl chain. The presence of a small mole fraction of an N-propionyl derivative of DPPE (N-C3:0-DPPE) diminishes cytochrome c affinity for vesicles containing a large amount of DPPG apparently by relieving the membrane packing strain that drives the extended DPPG conformation.
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The classic view holds that the medial temporal lobes (MTL) are dedicated to declarative memory functioning. Recent evidence, however, suggests that perirhinal cortex (PrC), a structure within the anterior MTL, may also play a role in perceptual discriminations when representations of complex conjunctions of features, or of gestalt-characteristics of objects must be generated. Interestingly, neuroimaging and electrophysiological recordings in nonhuman primates have also revealed a face patch in the anterior collateral sulcus with preferential responses to face stimuli in various task contexts. In the present fMRI study, we investigated the representational demands that influence PrC involvement in different types of judgments on human faces. Holding stimulus complexity constant, we independently manipulated the nature of the task and the orientation of the stimuli presented (through face inversion). Aspects of right PrC showed increased responses in a forced-choice recognition-memory and a perceptual-oddity task, as compared to a feature-search task that was included to probe visual detection of an isolated face feature. Effects of stimulus orientation in right PrC were observed when the recognition-memory condition for upright faces was compared with all other experimental conditions, including recognition-memory for inverted faces-a result that can be related to past work on the role of PrC in object unitization. Notably, both effects in right PrC paralleled activity patterns in broader networks of regions that also included the right fusiform gyrus and the amygdala, regions frequently implicated in face processing in prior research. As such, the current findings do not support the view that reference to a prior study episode clearly distinguishes the role of PrC from that of more posterior ventral visual pathway regions. They add to a growing body of evidence suggesting that the functional role of specific MTL structures may be best understood in terms of the representations that are required by the task and the stimuli at hand.
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Mapeamento Encefálico , Reconhecimento Visual de Modelos/fisiologia , Lobo Temporal/fisiologia , Adulto , Face , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Memória/fisiologia , Estimulação Luminosa , Adulto JovemRESUMO
Traditionally, the medial temporal lobe (MTL) is thought to be dedicated to declarative memory. Recent evidence challenges this view, suggesting that perirhinal cortex (PrC), which interfaces the MTL with the ventral visual pathway, supports highly integrated object representations in recognition memory and perceptual discrimination. Even with comparable representational demands, perceptual and memory tasks differ in numerous task demands and the subjective experience they evoke. Here, we tested whether such differences are reflected in distinct patterns of connectivity between PrC and other cortical regions, including differential involvement of prefrontal control processes. We examined functional magnetic resonance imaging data for closely matched perceptual and recognition memory tasks for faces that engaged right PrC equivalently. Multivariate seed analyses revealed distinct patterns of interactions: Right ventrolateral prefrontal and posterior cingulate cortices exhibited stronger functional connectivity with PrC in recognition memory; fusiform regions were part of the pattern that displayed stronger functional connectivity with PrC in perceptual discrimination. Structural equation modeling revealed distinct patterns of effective connectivity that allowed us to constrain interpretation of these findings. Overall, they demonstrate that, even when MTL structures show similar involvement in recognition memory and perceptual discrimination, differential neural mechanisms are reflected in the interplay between the MTL and other cortical regions.
Assuntos
Mapeamento Encefálico , Discriminação Psicológica/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Lobo Temporal/fisiologia , Vias Visuais/fisiologia , Face , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Rede Nervosa/irrigação sanguínea , Rede Nervosa/fisiologia , Testes Neuropsicológicos , Oxigênio/sangue , Estimulação Luminosa/métodos , Lobo Temporal/irrigação sanguínea , Vias Visuais/irrigação sanguíneaRESUMO
A series of four related phenol derivatives, with 2,2'-dipicolylamine substituents at the ortho positions, were prepared and their Zn2+ coordination complexes studied by spectroscopic methods. X-ray crystal diffraction analysis of a dinuclear zinc complex with two bridging acetate anions showed a ternary structure with highly charged interior and lipophilic exterior, which helps explain why this class of water-soluble complexes can effectively diffuse through cell membranes. The stability of the dinuclear zinc complexes in aqueous solution was found to be strongly anion dependent; that is, bridging oxyanions, such as acetate and pyrophosphate, lock the two Zn2+ cations to the surrounding ligand and greatly enhance ligand/zinc affinity. Overall, the results provide new insight into the structural and mechanistic factors that control the recognition and chemosensing performance of phenoxide bridged dipicolylamine molecular probes.
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A series of fluorescent phosphatidylserine and phosphatidylcholine derivatives were prepared and evaluated by cell microscopy for ability to translocate across mammalian plasma membranes via the putative aminophospholipid flippase. Phosphatidylserine derivatives, with either a neutral 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) or a coumarin fluorophore appended to the 2-acyl chain, entered the cytosol of all three cell lines tested and control experiments showed that the translocation was due to flippase activity. In contrast, a phosphatidylserine conjugate containing a charged and polar carboxyfluorescein was not translocated and remained in the cell plasma membrane. The phosphatidylserine-coumarin derivative exhibits bright fluorescence and higher photostability than the NBD analogues, and thus is a promising new fluorescent probe for extended-imaging studies of flippase action in living cells using laser confocal microscopes.
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Corantes Fluorescentes/metabolismo , Fosfatidilserinas/metabolismo , Proteínas de Transferência de Fosfolipídeos/metabolismo , Animais , Azóis/metabolismo , Transporte Biológico , Linhagem Celular , Cumarínicos/metabolismo , Fluoresceínas/metabolismo , Nitrobenzenos/metabolismoRESUMO
BACKGROUND: Six hospitals from the San Francisco Bay Area participated in a 12-month quality improvement project conducted by the Integrated Nurse Leadership Program (INLP). A quality improvement intervention that focused on improving medication administration accuracy was spread from two pilot units to all inpatient units in the hospitals. METHODS: INLP developed a 12-month curriculum, presented in a combination of off-site training sessions and hospital-based training and consultant-led meetings, to teach clinicians the key skills needed to drive organizationwide change. Each hospital established a nurse-led project team, as well as unit teams to address six safety processes designed to improve medication administration accuracy: compare medication to the medication administration record; keep medication labeled throughout; check two patient identifications; explain drug to patient (if applicable); chart immediately after administration; and protect process from distractions and interruptions. RESULTS: From baseline until one year after project completion, the six hospitals improved their medication accuracy rates, on average, from 83.4% to 98.0% in the spread units. The spread units also improved safety processes overall from 83.1% to 97.2%. During the same time, the initial pilot units also continued to improve accuracy from 94.0% to 96.8% and safety processes overall from 95.3% to 97.2%. CONCLUSION: With thoughtful planning, engaging those doing the work early and focusing on the "human side of change" along with technical knowledge of improvement methodologies, organizations can spread initiatives enterprisewide. This program required significant training of frontline workers in problem-solving skills, leading change, team management, data tracking, and communication.
Assuntos
Capacitação em Serviço/organização & administração , Sistemas de Medicação no Hospital/organização & administração , Recursos Humanos de Enfermagem Hospitalar/organização & administração , Melhoria de Qualidade/organização & administração , Gestão da Segurança/organização & administração , Coleta de Dados/métodos , Documentação/métodos , Humanos , Sistemas de Identificação de Pacientes , Desenvolvimento de ProgramasRESUMO
The US health care system is reaching a critical point. Consistent cost increases coupled with a struggling economy has illuminated the burden of more than $650 billion annually in health care expenditures. The ability to afford health care is a growing concern for individuals, businesses, and state and federal governments. In addition to costs, variability in quality, and utilization belie any claims of a rational and consistent system of care. Transformational change will require leaders to shape our future health care institutions. Nursing has historically not been considered as a leadership source for change of this magnitude. However, due to the sheer size of nursing, core skills, and competencies, nurses could be a viable resource. Competencies needed for nurse, health care, and physician executives were compared using the HealthCare Leadership Alliance data, which created a body of knowledge that identifies competencies in 5 domains. Findings demonstrate that nurses, health care executives, and physicians possess more than 80% of the competencies reviewed. To successfully take on the role of leading institutional response to the dramatically changing health care environment, nurses must not only have the requisite leadership skills and experience, they must also have an expectation of themselves to lead at this level.